How a full wave rectifier works

Full-wave Rectifier with Smoothing Capacitor
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The smoothing capacitor converts the full-wave rippled output of the rectifier into a smooth DC output voltage. Generally for DC power supply circuits the smoothing capacitor is an Aluminium Electrolytic type that has a capacitance value of 100uF or more with repeated DC voltage pulses from the rectifier charging up the capacitor to peak voltage. However, their are two important parameters to consider when choosing a suitable smoothing capacitor and these are its Working Voltage, which must be higher than the no-load output value of the rectifier and its Capacitance Value, which determines the amount of ripple that will appear superimposed on top of the DC voltage. Too low a value and the capacitor has little effect but if the smoothing capacitor is large enough (parallel capacitors can be used) and the load current is not too large, the output voltage will be almost as smooth as pure DC. As a general rule of thumb, we are looking to have a ripple voltage of less than 100mV peak to peak

Sonic-connect 2 helps your messages get organized

We live in an extremely busy world these days, where our attention tend to be pulled in different directions, and the kind of mobile devices that we own allow us to be in constant communication with other folks round the clock, so much so that sometimes, we tend to experience a condition that I would say amounts to information overload. Emails, Facebook messages, text messages, tweets, Instagram photos, there are just too many avenues available to get swamped with information, so what are some of the tools available to help those of us who are swimming in messages and communication loops? Sonic Alert’s Sonic-connect 2 might just do the trick, with this being a portable USB device that is said to alert you to the most important incoming messages which arrive on your computer.

How does it achieve this? Is it done through some sort of sorcery, or just clever engineering? The Sonic-connect 2 will basically be able to rank contacts according to your preference, so that you are able to be alerted to all new messages, or only to receive messages from select VIPs. With the Sonic-connect 2, you now have the power in your hands to prioritize your responses, while providing you with the relevant freedom to step away from your computer without having to miss out on important communication. Of course, I would say that the biggest weakness in this device is the fact that it places total responsibility on the human to get its parameters right.

You will find that the Sonic-connect 2 will feature a range of customizable alert options, where among them include extra-bright white LED lights, loud ringer and vibration to alert you to incoming news from Skype, IM and Microsoft Outlook. Using it is a snap, all you need to do is hook up the device to your desktop or laptop USB port, and in just minutes, you are able to receive message alerts via flash, vibration or beeping.

ABB solves 100-year-old electrical puzzle – new technology to enable future DC grid

Development of a DC breaker for high voltage transmission will help shape the grid of the future

Zurich, Switzerland, Nov. 7, 2012 – ABB, the leading power and automation technology group, today announced a breakthrough in the ability to interrupt direct current, solving a 100-year-old electrical engineering puzzle and paving the way for a more efficient and reliable electricity supply system.

After years of research, ABB has developed the world’s first circuit breaker for high voltage direct current (HVDC). It combines very fast mechanics with power electronics, and will be capable of ‘interrupting’ power flows equivalent to the output of a large power station within 5milliseconds- that is thirty times faster than the blink of a human eye.

The breakthrough removes a 100-year-old barrier to the development of DC transmission grids, which will enable the efficient integration and exchange of renewable energy. DC grids will also improve grid reliability and enhance the capability of existing AC (alternating current) networks. ABB is in discussions with power utilities to identify pilot projects for the new development.

“ABB has written a new chapter in the history of electrical engineering,” said Joe Hogan, CEO of ABB. “This historical breakthrough will make it possible to build the grid of the future. Overlay DC grids will be able to interconnect countries and continents, balance loads and reinforce the existing AC transmission networks. “

The Hybrid HVDC breaker development has been a flagship research project for ABB, which invests over $1 billion annually in R&D activities. The breadth of ABB’s portfolio and unique combination of in-house manufacturing capability for power semiconductors, converters and high voltage cables (key components of HVDC systems) were distinct advantages in the new development.

HVDC technology is needed to facilitate the long distance transfer of power from hydropower plants, the integration of offshore wind power, the development of visionary solar projects, and the interconnection of different power networks. ABB pioneered HVDC nearly 60 years ago and continues to be a technology driver and market leader with many innovations and developments. With over 70 HVDC projects, ABB accounts for around half the global installed base, representing an installed capacity of more than 60,000 megawatts (MW).

Deployment of HVDC has led to an increasing number of point-to-point connections in different parts of the world. The logical next step is to connect the lines and optimize the network. ABB is already working on the construction of multi-terminal systems and the latest DC breaker innovation is a major step in the evolution of HVDC grids. In parallel to the new hybrid breaker development, ABB has an established HVDC grid simulation center developing solutions for future DC overlay grid operations.

For more information, multimedia material or to speak to ABB experts please click here.

ABB (www.abb.com) is a leader in power and automation technologies that enable utility and industry customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries and employs about 145,000 people.

Brick Joystick for Smartphone Gaming

Brick Joystick for Smartphone Gaming

The Brick is the ultimate smartphone joystick, superior to all other versions of joysticks in the marketplace. It demonstrates the most outstanding operability and adjustability amongst the competition.Experience minimal screen blocking, reduced thumb fatigue and an overall more intimate gameplay feeling.

Portable Charging Station with Battery Pack

Portable Charging Station with Battery Pack

The Reinvented Portable Charging Station, Charge Anytime, Anywhere.The new and improved Portable Charging Station with Integrated 5200mAh Battery Pack. You get all the great features of the Portable Charging Station such as attached 4-Port USB Hub, detachable wall adapter, Cable Rack System for cable management and the compact portable zipper bag that neatly organizes all these things, however now you get the added bonus of an integrated 5200mAh lithium ion battery so you can now truly charge your devices on the go anytime, anywhere

CUTTING BOARD THAT WEIGHS WHAT YOU CUT

Design Concept: Cutting Board with Embedded Scale

This design concept by Jess Griffin and Jim Termeer is a cutting board with an embedded scale in a circular area on its right half, telling you the exact weight of those ingredients you're about to place into your recipe or on your plate. The 10"x15" cutting board is designed to use electronic ink to display weight, with embedded sensor grids underneath the surface to determine the downward force of objects placed on it.

Don't be getting out that credit card just yet; the designers say the technology to build the thing is between one and five years away. The electronic ink display technology will be possible between one and five years from now, the low-current photovoltaics specified as its power source will be practical in one to three years, and the embedded sensor grids are also one to three years away.

We're thinking this is almost feasible now, but still cost-prohibitive for incorporation into a consumer product. Great idea for chefs and dieters, too, though. Maybe it could be done with more-conventional tech. – Charlie White

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What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 5 Hz (frequency) source of the same voltage?

What is the difference between Power Transformers and Distribution Transformers?

Those transformers installed at the ending or receiving end of long high voltage transmission lines are the power transformers. The distribution transformers (generally pole mounted) are those installed in the location of the city to provide utilization voltage at the consumer terminals.

•  Power transformers are used in transmission network of higher voltages for step-up and step down application (400 kV, 200 kV, 110 kV, 66 kV, 33kV) and are generally rated above 200MVA.
• Distribution transformers are used for lower voltage distribution networks as a means to end user connectivity. (11kV, 6.6 kV, 3.3 kV, 440V, 230V) and are generally rated less than 200 MVA.
• A power transformer usually has one primary and one secondary, and one input and output. A distribution transformer may have one primary and one divided or "Tapped" secondary, or two or more secondaries.
• Power transformers generally operate at nearly full – load. However, a distribution transformer operates at light loads during major parts of the day.
• The performance of the power transformers is generally judged from commercial efficiency whereas the performance of a distribution transformer is judged from all – day – efficiency.
• The rating of a high transformer is many times greater than that of distribution transformer.
• In Power Transformer the flux density is higher than the distribution transformer.
• Power transformer's primary winding always connected in star and secondary winding in delta while in distribution transformer primary winding connected in delta and secondary in star.
• In The Sub station end of the transmission line, The Power Transformer Connection is Star-Delta.( For the purpose of Step down the Voltage Level)
• In the star up of the  Transmission line (H-T), The Connection of the power Transformer is Delta – Star (For the purpose of Step Up the Voltage Level) But in case of Distribution Transformer, But Generally it is used in there-phase Step down distribution transformer( Delta – Star)                                              

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